 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal;

 import org.eclipse.jface.action.Action;
 import org.eclipse.ui.IPageListener;
 import org.eclipse.ui.IPartListener;
 import org.eclipse.ui.IWorkbenchPage;
 import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.actions.ActionFactory;

 /**
  * Implements an action to open a list of open editors in the
  * currently or last active workbook
  *
  * @since 3.0
  */
 public class WorkbookEditorsAction extends Action implements
         ActionFactory.IWorkbenchAction, IPageListener, IPartListener {

     /**
      * The workbench window; or <code>null</code> if this
      * action has been <code>dispose</code>d.
      */
     private IWorkbenchWindow workbenchWindow;

     /**
      * Constructor for NavigateWorkbenchAction.
      */
     public WorkbookEditorsAction(IWorkbenchWindow window) {
         super(WorkbenchMessages.WorkbookEditorsAction_label);
         if (window == null) {
             throw new IllegalArgumentException ();
         }
         this.workbenchWindow = window;
         // Do we need help here ?
 //WorkbenchHelp.setHelp(this, IHelpContextIds.WORKBENCH_EDITORS_ACTION);
 setActionDefinitionId("org.eclipse.ui.window.openEditorDropDown"); //$NON-NLS-1$
 workbenchWindow.addPageListener(this);
         workbenchWindow.getPartService().addPartListener(this);
         updateState();
     }

     /* (non-Javadoc)
      * Method declared on IAction.
      */
     public void run() {
         if (workbenchWindow == null) {
             // action has been disposed
 return;
         }
         IWorkbenchPage page = workbenchWindow.getActivePage();
         if (page != null) {
             WorkbenchPage wbp = (WorkbenchPage) page;
             EditorAreaHelper eah = wbp.getEditorPresentation();
             if (eah != null) {
                 eah.displayEditorList();
             }
         }
     }

     /* (non-Javadoc)
      * Method declared on ActionFactory.IWorkbenchAction.
      */
     public void dispose() {
         workbenchWindow.removePageListener(this);
         workbenchWindow.getPartService().removePartListener(this);
         workbenchWindow = null;
     }

     /**
      * Updates the enabled state.
      */
     public void updateState() {
         IWorkbenchPage page = null;
         if (workbenchWindow != null) {
             page = workbenchWindow.getActivePage();
         }
         if (page == null) {
             setEnabled(false);
             return;
         }
         // enable iff there is at least one other editor to switch to
 setEnabled(page.getEditorReferences().length >= 1);
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPageListener#pageActivated(org.eclipse.ui.IWorkbenchPage)
      */
     public void pageActivated(IWorkbenchPage page) {
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPageListener#pageClosed(org.eclipse.ui.IWorkbenchPage)
      */
     public void pageClosed(IWorkbenchPage page) {
         updateState();
     }

     public void pageOpened(IWorkbenchPage page) {
         updateState();
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPartListener#partActivated(org.eclipse.ui.IWorkbenchPart)
      */
     public void partActivated(IWorkbenchPart part) {
         //no-op
 }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPartListener#partBroughtToTop(org.eclipse.ui.IWorkbenchPart)
      */
     public void partBroughtToTop(IWorkbenchPart part) {
         //no-op
 }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPartListener#partClosed(org.eclipse.ui.IWorkbenchPart)
      */
     public void partClosed(IWorkbenchPart part) {
         updateState();
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPartListener#partDeactivated(org.eclipse.ui.IWorkbenchPart)
      */
     public void partDeactivated(IWorkbenchPart part) {
         //no-op
 }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPartListener#partOpened(org.eclipse.ui.IWorkbenchPart)
      */
     public void partOpened(IWorkbenchPart part) {
         updateState();
     }
 }

